Justice and Science on NPR

This morning on The Diane Rehm Show, guest host Susan Page and George Clarke, a former prosecutor and now a Superior Court judge in San Diego, discussed the evolution of DNA evidence in criminal cases and its role in determining guilt and innocence.

You can listen to the program in both Real Audio format and in Windows Media.

The program included discussion of the power of DNA to exonerate the innocent. There remains, however, a mythical perception that DNA is omnipresent in murder cases and can therefore guarantee certainty in all convictions. As we've written before, DNA evidence is available in fewer cases than most people would suspect. A New York Times article from April 19, 2004 provided the following points from a study of exonerations:

In 88 percent of the rape cases in the study, DNA evidence helped free the inmate. But biological evidence is far less likely to be available or provide definitive proof in other kinds of cases. Only 20 percent of the murder exonerations involved DNA evidence, and almost all of those were rape-murders.

Additionally, the Death Penalty Information Center's list of death row exonerees points out that only 16 of the 127 exonerations had DNA evidence as a substantial factor in establishing innocence. Neither of Indiana's two exonerations involved DNA evidence.